Parameters for Hydrolytic Degradation

The hydrolytic degradation mechanism, rate, and behavior are affected by the parameters of materials and media, as summarized in Table 21.2. The material parameters include molecular and highly ordered structures, additives including other polymers and fibers, and the material morphology. The medium parameters include the type and concentrations of catalytic species and other solutes, pH, temperature, and the type and density of microbes. 

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Thus, considering the high importance of the appropriate hydrolytic degradation rate of PLA when this is utilized for its recycling to lactic acid or as biomedical materials with an optimal degradation rate in the human body (as pharmaceutical matrices), the aim of this chapter is to review the recent studies reported in the literature on the mechanisms, affecting parameters and possible applications of the abiotic hydrolytic degradation of PLA. 

The control of the PLA hydrolytic degradation is necessary for medical applications and for the plastics industry. The mechanism of abiotic-hydrolytic degradation as well as the rate of degradation reaction for PLA-based materials seems to be affected by a wide variety of compositional and property variables, as reported in this chapter. Consequently, knowing and understanding all parameters could bring the possibility to control in a certain vray... 

PPDX fulfills the criteria of bioresorbability and biocompatibility, as assessed by cell adhesion and cell growth. In addition, the products as generated by hydrolytic degradation of PPDX did not provide any cytotoxicity, representing a cmdal parameter in view of using degradable polymers such as PPDX for biomedical applications. ... 

Hydrolytic and radiolytic degradation of TAP solution in normal paraffinic hydrocarbon (NPH) in the presence of nitric acid was investigated. Physicochemical properties such as density, viscosity, and phase-disengagement time (PDT) were measured for undegraded and degraded solutions (197). The variations in these parameters were not very different from those obtained with degraded TBP. Thus, the hydro-dynamic problems expected during the solvent-extraction process with TAP would be similar to those encountered with TBP/NPH system. The influence of chemical... 

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